Regulated dashpot with shock-absorption force controls

ABSTRACT

A regulable dashpot with shock-absorption force controls, especially intended for motor vehicles, with at least one flow-regulating system including one or more shock-absorption components for the compression phase and/or for the decompression phase. The object is to allow the dashpot to shift continuously between the hard and soft phases, whereby the valve-adjustment intervals can be varied at intervals that are not unnecessarily short or even unattainable. At least one valve assembly is accordingly supplied with variable flow impedance by a regulating valve ( 5  or  6 ).

[0001] The present invention concerns a regulated dashpot withshock-absorption force controls, especially intended for motor vehicles,as recited in the preamble to claim 1.

[0002] Regulated hydraulic dashpots with flow-regulating system thatshift back and forth between compression and decompression phases inoperation are known. Dashpots of this genus are described in German 3803 838 C2 for instance.

[0003] There is a drawback to such dashpots in that their design permitsthem to shift only suddenly between the hard and soft phases, limitingthe range of control. The comfortability of the ride can be increasedonly to a limited extent.

[0004] The object of the present invention is accordingly a dashpot ofthe aforesaid genus that can shift continuously between the hard andsoft phases, whereby the valve-adjustment intervals can be varied atintervals that are not unnecessarily short or even unattainable.

[0005] This object is attained by the characteristics recited inclaim 1. Advantageous and advanced embodiments are addressed in claims 2through 8.

[0006] The present invention has many advantages. A continuoustransition between hard and soft phases can be obtained by simple means.Valve-adjustment intervals can be maintained long enough to allow thedevice to be manufactured at justifiable component costs and to beoperated at low requisite adjustment powers.

[0007] One particular advantage is that the flow-regulating system canbe modular and employed in different vehicles with variousshock-absorption performances. Since there will be no sudden jolts whenshifting between the hard and soft phases and vice versa, riding comfortwill be considerably improved.

[0008] Various embodiments of the present invention will now bespecified by way of example with reference to the accompanying drawing,wherein

[0009]FIG. 1 is a schematic illustrating how a dashpot can be regulatedin accordance with a single-chamber principle,

[0010]FIGS. 2 through 11 are schematics illustrating various otherapproaches to regulation in accordance with the single-chamberprinciple,

[0011]FIGS. 12 and 13 are schematics illustrating how a dashpot can beregulated in accordance with a resilient-chamber principle and with atwo-chamber principle, and FIG. 14 is a schematic illustratingregulation inside a dashpot cylinder.

[0012] The figures illustrate hydraulic circuitry specific to variousdashpots. Each dashpot includes a piston 3 mounted on the end of apiston rod 2 and traveling back and forth inside a cylinder 1. Areservoir 4 contains a compressed gas that compensates for the volume ofhydraulic fluid displaced by piston 3. Reservoir 4 can be integratedinto the dashpot.

[0013]FIG. 1 illustrates the hydraulic circuitry for a dashpot inaccordance with the present invention. The dashpot includes twohydraulically parallel regulating valves 5 and 6. Hydraulicallyparalleling both regulating valves 5 and 6 is a very narrowlyconstricted bypass valve 7, which can alternatively be integrated intoone or both regulating valves. Bypass valve 7 provides a minimal passagefor the hydraulic fluid and accordingly prevents the dashpot from beingentirely blocked while regulating valves 5 and 6 are closed. Whenclosed, regulating valves 5 and 6 provide continuous regulation of thetwo phases and, when closed, allow the fluid to flow. Regulating valve 5regulates the flow while piston 3 is traveling in the compressiondirection and regulating valve 6 regulates it while the piston istraveling in the decompression direction. The rate of flow depends onthe one hand on the difference between the pressure in an upper chamber8 and that in a lower chamber 9, the two chambers being separated bypiston 3, and on the other hand on the cross-section of the passagethrough regulating valves 5 and 6 as dictated by flow controls likethose known from German Patent 10 040 518.

[0014]FIG. 2 illustrates another embodiment of the circuitry illustratedin FIG. 1. In this embodiment, fluid can flow through both regulatingvalves 5 and 6 from either end as long as they are open, and theoperative direction is prescribed by external checkvalves 10 and 11.

[0015]FIG. 3 illustrates an advanced version of the circuitryillustrated in FIG. 2. It employs spring-loaded checkvalves 12 and 13instead of the external checkvalves 10 and 11. Such checkvalves willopen to an extent that depends on the difference in pressure betweenchambers 8 and 9. The type of springs employed determine the intendedperformance curve of the dashpot in both compression and thedecompression phases.

[0016]FIG. 4 illustrates an advanced version of the circuitryillustrated in FIG. 3. It includes a valve assembly 18 comprisingunregulated spring-loaded checkvalves 16 and 17 that parallel regulatedspring-loaded checkvalves 12 and 13. Checkvalves 16 and 17 parallel eachother hydraulically and operate independently in both the compressionand the decompression phases. Valve assembly 18 can be integrated intopiston 3 and acts as a standard spring loaded piston. The performancecurve for valve assembly 18 is set to “hard” and that of regulatedspring-loaded checkvalves 12 and 13 to “soft”. Regulating valves 5 and 6can accordingly now switch independently of each other and continuouslyback and forth between hard and soft in both the compression and thedecompression phases. In addition to bypass valve 7, bypass valves 19and 20 can be introduced paralleling spring-loaded checkvalves 12 and13.

[0017] This embodiment ensures constantly reliable driving performanceeven when the electricity or electronics fail. In such an event,regulating valves 5 and 6 will substantially close, and continuedoperation of the dashpot will be ensured by the mechanical action of thespring-loaded checkvalves 16 and 17 in valve assembly 18 at a hardperformance curve, preferably within piston 3, that is.

[0018] The embodiment illustrated in FIG. 5 lacks the regulatedspring-loaded checkvalves 12 and 13 employed in the embodimentillustrated in FIG. 4. This embodiment is an advanced version of theregulable dashpot illustrated in FIG. 1, employing a parallel valveassembly 18 like that in the version illustrated in FIG. 4. The bypassvalve can also be eliminated.

[0019]FIG. 6 illustrates an alternative to the embodiment illustrated inFIG. 5. Paralleling a valve assembly 18 that comprises unregulatedspring-loaded checkvalves 16 and 17 with their hard performance curveare two similar spring-loaded checkvalves 12 and 13 with a softperformance curve. Checkvalves 12 and 13 can be brought into play by wayof associated hydraulic switches 21 and 22, allowing a soft performancecurve to be introduced while piston 3 is traveling in either thecompression or the decompression direction. Paralleling these are twoparallel one-way checkvalves 23 and 24 with a soft performance curvethat can be actuated and regulated by a regulating valve 25. Thiscircuitry again allows the shock-absorption performance curves to beestablished anywhere between hard and soft independently of each otheras desired with the piston traveling in either direction.

[0020] Circuitry similar to that illustrated in FIG. 6 can be attainedas illustrated in FIG. 7. The soft checkvalves 12 and 13 in thisembodiment are provided with a two-to-three way valve 26 instead of twoindividual switching valves.

[0021]FIG. 8 illustrates another alternative embodiment. A valveassembly 27 comprises two spring-loaded checkvalves 28 and 29, eachpermitting the flow in a direction opposite that of the other.Checkvalves 28 and 29 have a soft performance curve and are alternatelycontrolled by a two-to-three way valve 30. A flow-regulating valve 31continuously opens or closes a parallel hydraulics line 32. Aconstricted bypass valve 33 ensures minimal unimpeded flow.

[0022]FIG. 9 illustrates an advanced version of the of the embodimentillustrated in FIG. 8. Upstream of flow-regulating valve 31 is a valveassembly 34 comprising two spring-loaded opposed-flow checkvalves 35 and36. Checkvalves 35 and 36 also have a soft performance curve, althoughthis curve can be varied between hard and soft. Bypass valve 33, which,like the one illustrated in

[0023]FIG. 8, can parallel flow-regulating valve 31, two-to-three wayvalve 30, and/or the two series comprising a regulation-and-switchingvalve and checkvalves 35 and 36 or checkvalves 28 and 29, again ensuresminimal flow as long as two-to-three way valve 30 and flow-regulatingvalve 31 are closed.

[0024]FIG. 10 also illustrates an advanced version of the embodimentillustrated in FIG. 8. This version includes, paralleling the componentsillustrated in FIG. 8, another, unregulable, valve assembly 37comprising spring-loaded opposed-flow checkvalves 38 and 39. Checkvalves38 and 39 have a hard performance curve and can preferably be integratedinto the piston in the form of standard cupspring-loaded valves.

[0025]FIG. 11 illustrates another advanced version of the embodimentillustrated in FIG. 8. It includes a valve assembly 27 comprisingspring-loaded opposed flow checkvalves 28 and 29 with a soft performancecurve, their direction of flow being reversed by a two-to-three wayvalve 30. The flow-regulating valve 31 in this embodiment, however,parallels valve 30, constantly maintaining the valve assembly 27comprising checkvalves 28 and 29 in series with the latter. Thisembodiment also includes a constricted bypass valve 33 that ensuresminimal flow.

[0026] The flow-regulating assembly 40 represented by the dot-and-dashlines in FIGS. 1 through 11 is depicted in the form of a preferablyself-contained block 41 in FIGS. 12 and 13. Flow-regulating block 41 canalso communicate with valve assembly 18, 27, 34, or 37.

[0027] The flow-regulating block 41 represented in FIG. 12 ishydraulically interposed between lower cylinder chamber 9 andpressure-compensating gas reservoir 4.

[0028]FIG. 13 illustrates a double-cylinder dashpot with a valveassembly 42 comprising two spring-loaded checkvalves 43 and 44integrated into its piston 3. A bottom valve 46 in the form of aspring-loaded one-way valve is interposed between lower cylinder chamber9 and a pressure-compensating reservoir represented by the space 45between the cylinder's walls. The flow regulating assembly is preferablyagain in the form of a self-contained block 41 located outside thedashpot and hydraulically interposed between cylinder chambers 8 and 9.

[0029] The hydraulic switching-and-regulating components in theembodiment illustrated in FIG. 14 are integrated, like the componentsillustrated in FIG. 11, into the dashpot's piston 3.

List of Parts

[0030]1. cylinder

[0031]2. piston rod

[0032]3. piston

[0033]4. reservoir

[0034]5. regulating valve

[0035]6. regulating valve

[0036]7. constricted bypass valve

[0037]8. upper cylinder chamber

[0038]9. lower cylinder chamber

[0039]10. checkvalve

[0040]11. checkvalve

[0041]12. checkvalve

[0042]13. checkvalve

[0043]14. compression spring

[0044]15. compression spring

[0045]16. checkvalve

[0046]17. checkvalve

[0047]18. valve assembly

[0048]19. constricted bypass

[0049]20. constricted bypass

[0050]21. hydraulic switch

[0051]22. hydraulic switch

[0052]23. checkvalve

[0053]24. checkvalve

[0054]25. flow-regulating valve

[0055]26. two-to-three way valve

[0056]27. valve assembly

[0057]28. checkvalve

[0058]29. checkvalve

[0059]30. two-to-three way valve

[0060]31. flow-regulating valve

[0061]32. hydraulics line

[0062]33. constricted bypass valve

[0063]34. valve assembly

[0064]35. checkvalve

[0065]36. checkvalve

[0066]37. valve assembly

[0067]38. checkvalve

[0068]39. checkvalve

[0069]40. flow-regulating assembly

[0070]41. flow-regulating block

[0071]42. valve assembly

[0072]43. checkvalve

[0073]44. checkvalve

[0074]45. intermural space

[0075]46. bottom valve

1. Regulated dashpot with shock-absorption force controls, especially intended for motor vehicles, with at least one flow-regulating system including one or more shock-absorption components for the compression phase and/or for the decompression phase, characterized in that at least one valve assembly is supplied with variable flow impedance by a regulating valve (5, 6, 26, or 31).
 2. Dashpot as in claim 1, characterized by at least one fixed bypass valve (7, 19, 20, or 33) with a constricted cross-section hydraulically paralleling the flow-regulating systems.
 3. Dashpot as in claim 1 or 2, characterized by at least one flow regulating system for the compression phase and at least one for the decompression phase in the form of regulating valves (5 & 6) with a variable flow constriction.
 4. Dashpot as in one or more of claims 1 through 3, characterized by previously adjusted pressure-dependent valve assemblies (18) with a fixed flow cross-section for the compression and/or decompression phase and with a hard performance curve, hydraulically paralleling the flow-regulating and/or shock absorption systems.
 5. Dashpot as in one or more of claims 1 through 4, characterized by previously adjusted pressure-dependent valve assemblies (18) with a fixed flow cross-section for the compression and/or decompression phase and with a soft performance curve, that can be activated and deactivated individually or separately, hydraulically paralleling the flow-regulating and/or shock absorption systems.
 6. Dashpot as in one or more of claims 1 through 5, characterized in that the flow-regulating, flow-constricting, or shock-absorption systems are accommodated in a separate component, preferably in the form of a flow regulating block (41) outside the dashpot and communicating with it by way of hydraulic-fluid lines.
 7. Dashpot as in one or more of claims 1 through 5, characterized in that the flow-regulating, flow-constricting, or shock-absorption systems are accommodated in or on its piston (3).
 8. Dashpot as in one or more of claims 1 through 5, characterized in that the flow-regulating, flow-constricting, or shock-absorption systems are accommodated in or on its bottom valve (46). 